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If the pressure is good that means the solenoid is working fine but I can disconnect to avoid stuck issues in the future BUT if the pressure is bad that means it is stuck and definitely needs disconnecting correct?
Truth being told...
there are not a lot of MB engines with jammed solenoids - They are all RIP in a junk yard!
Personal decision knowing junk-yard predicament is :
measure oil pressure above 40psi
then either disconnect (MOD-1) or stay stock (MOD-0) ?
else simply assume "not blown up" means ok!
> Geek club: NO IN/OUT PRIVILEGE...
-- Generally speaking unplugged seems safer than plug-in under most conditions UNTIL re-plugging may jam solenoid with stored particulates.
-- Therefore unplugging is safest only as a one way process to avoid possible reconnection jams. (some ppl been lucky reconnecting: ok).
> OTHER GOTCHA...
-- We're experimenting for all the good and none of the bad.
-- Engine needs (viscosity upgrade to get) effective spray-cooling at driving Rpm.
-- The oil seal improvement is very effective at artificially balancing drafty cylinders which can be bad with high outputs (redline/WOT).
-- To redline a TT best requires a balanced clean-rings sealed engine. Once rings have cleaned up then ramp up viscosity and enjoy full Rpm range.
> PRACTICALLY:
-- Take your time stepping up viscosity to let newly cooled wet rings clean-up loose from burnt oil carbon.
-- Brake booster improvements will acknowledge seal improvements from lower crankcase pressure.
-- Evidence keep pilling up to stress importance of ESP/ECU/TCU timings for pressure sensitive GDI throttle... touchy sensitive factor.
> HONEST GOODNESS...
-- This experiment shows us there is a whole stack of lost engine-tranny performance available to be reclaimed with specific setup on vanilla-stock firmware.
-- Factors that can affect smooth timings de-tune GDI output... duh! Sounds trivial now, right?
VVT Positioning: low oil pressure spikes
Voltage swings: exact spark timing
Reboot + Float: sparks and CAN thresholds
CAN-C Networking bandwidth: delays ECU + TCU
Uncontrolled heat: affects VVT+Tranny work
> GOING WHERE/HOW...
-- Bosch ECU is simply a giant tic-toc-clock system that dislikes chaos >> More stable timings works best.
-- We realize what is most touchy to tweak is: The combustion event is the Genesis of performance...duh!
-- We're tweaking out variables to help the ECU core processes make each combustion event best.
BTW... Germany Gvt was just forced to restart its military greatness with $300 Billion budget.
Give it 5 years for the next WWIII installment.
A blood bath must go on... God bless humanity.
🤞
Last edited by CaliBenzDriver; Mar 2, 2025 at 06:54 PM.
Based on Master Surya's research it seems Mercedes-Bosch further reshuffled the cards.
In M256 MB uses "multiple oil pressures".
The VVT can get full pressure while
The pistons get low pressure....
That means room for reliability improvements.
> What To Do...:
You'll want to select the targets you want to experiment with.
It may well be you only need better viscosity to help spray pistons heat away.
That in itself is a tall order because oiling helps timings that help heat meaning its not only the oil that directly drops heat after the 1st Mile. It's the ECU adapting its maps over x-many miles.
There's a chance the M256bcamshaft positioning is now reliable ONCE PROVIDED WITH PROPER PRESSURE.
Meaning do not expect VVT effectiveness on MB stock 10kMi thin oil.
You want to pionner effective VVT pressure & piston spray. We'll help ya read your tea leaves.
From WIS perspective MB still minimizes everything to save gasoline fumes.
++++ TRANSLATION...
the way I understand M256 setup is a conventional single pressure pump supplying VVT and using a solenoid to limit piston sprayers.
Note that when you enable the piston sprayers you NEED ENOUGH PUMP VOLUME/PRESSURE AVAILABLE not to starve existings.
Again that sounds like better viscosity is gonna be your ticket.
Meaning you don't want to starve engine head(s) to spray pistons on thin oil at 1500.Rpm: can't do!!
Practically assess stock engine issues...
-- Engine poor throttle control ??
-- Gearbox sloppy shifts ??
-- Extreme heatsoaks ??
-- New issue ...
Based on your inputs we can help.
Reporting back before I go to 5w-40 or 0w-40. Still not sure where to go.
ANYWAYS it has now been one full month of owning the car, drove 3000 miles on it (i go back and forth between AZ and CA alot).
Noted that when car was first purchased, oil temps are holding steady at 210 to 215F for normal operation. This includes freeway, normal driving, and spirited driving, all bundled into one.
After many miles of driving a little above the speed limit.
After three long distance drives (between LA and PHX) it would seem that the ECU in this case is starting to learn. I am now holding stable 225F through long distance operation, something indicative of piston cooling that we have discussed before. No true improvement yet in throttle responsiveness but the M256 with it's double-charging setup is already very responsive as is.
However I will note that flooring it in Sport+ offers maybe? incrementally faster shifts. It would stand to reason that MB saw that it could learn from the mistakes of the M278/M157 and adapt a more responsive piston cooling setup for drivers who will use their engine more agressively. (i fall into that category.)
Currently still completely unable to find oil pressure port. Literature is offering no help.
This is basically a pseudo MOD-2-3 or whatever (idk what you guys use to describe the stages of improvement) but I want to see if raising viscosity will improve the cooling.
The best research for M256 owner is to buy its piston cooling oil jet/squiters, just like me buying my M276.8 piston oil jet to learn of its technical charateristic.
Since M276.9 or .8 and M278 and M157 does not have the split oiling system of M256, there is a possibility that M256 oil cooling jet has no ball-spring, but open hole all the way,
unlike our M276.9 or .8 and M278 and M157 where the oil jet has its own pressure regulation using ball + spring built into the oil jet itself....cheap regulation, can fail too !!!
If M256 piston cooling oil jet is open hole, it then need another means to stop its oil spraying by using solenoid ( valve ), when not needed.
Otherwise at idle the oil jets will east up the oil flow/pressure budget so much.... the rest of the oil-dependent mechanicals inside the engine will suffer.
Just like dating girls, where we want to know more of her, you need to buy her dinner and yada yada...... may be not in Holland, thus there is a term called Let's go On Dutch on our 1st date
The same for our cars, we need to buy scanners and some parts/tools yada yada where when we want to learn of its crucial function/behaviour.
Going to a good university like NYC cost $$,$$$ per year , thus learning of our cars will need effort and $ too.
Reporting back before I go to 5w-40 or 0w-40. Still not sure where to go.
ANYWAYS it has now been one full month of owning the car, drove 3000 miles on it (i go back and forth between AZ and CA alot).
Noted that when car was first purchased, oil temps are holding steady at 210 to 215F for normal operation. This includes freeway, normal driving, and spirited driving, all bundled into one.
After many miles of driving a little above the speed limit.
After three long distance drives (between LA and PHX) it would seem that the ECU in this case is starting to learn. I am now holding stable 225F through long distance operation, something indicative of piston cooling that we have discussed before. No true improvement yet in throttle responsiveness but the M256 with it's double-charging setup is already very responsive as is.
However I will note that flooring it in Sport+ offers maybe? incrementally faster shifts. It would stand to reason that MB saw that it could learn from the mistakes of the M278/M157 and adapt a more responsive piston cooling setup for drivers who will use their engine more agressively. (i fall into that category.)
Currently still completely unable to find oil pressure port. Literature is offering no help.
This is basically a pseudo MOD-2-3 or whatever (idk what you guys use to describe the stages of improvement) but I want to see if raising viscosity will improve the cooling.
You're interested to depart from stock MOD-0 to gain pistons cooling at normal driving RPM.
You'll need to first enable normal oil pressure and switch to MOTUL, AMSOIL, CASTROL 5W40 to begin with.
Last edited by CaliBenzDriver; Mar 3, 2025 at 04:17 AM.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by exturnul
... I am now holding stable 225F through long distance operation, something indicative of piston cooling that we have discussed before.
225°F seems a bit high. Even 210°F to 215°F are unusual temperatures for either of my cars.
What is the ambient temperature where you drive?
Do we know if the M256 uses an actual oil temperature sensor or is it calculated like the M276, M278, etc. engines?
Which vehicle are you driving? You show multiple cars that use the M256 engine. Do they all behave this way?
I've tried to find how to measure the oil pressure for the M256 in the WIS, but am unable to. Seems very strange that Mercedes would not provide that ability for diagnostic purposes. Since the M256 is relatively new, I would want to know more about it before messing with disconnecting anything.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
I did find these instructions for measuring oil pressure on the GLS450, but it is all through XENTRY and not physically. That tells me that the M256 has an oil pressure sensor.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
What is crazy is that the MAXIMUM oil pressure for the M256 at 3000 rpm is 1.7 bar (or 25 psi), about half of what you want to see in the M276, etc. I definitely would not be disconnecting any controls without first understanding what is going on.
What is crazy is that the MAXIMUM oil pressure for the M256 at 3000 rpm is 1.7 bar (or 25 psi), about half of what you want to see in the M276, etc. I definitely would not be disconnecting any controls without first understanding what is going on.
Great cautionary, will advise forum members to go to this post when they have a M256 asking about it moving forward.
I did find these instructions for measuring oil pressure on the GLS450, but it is all through XENTRY and not physically. That tells me that the M256 has an oil pressure sensor.
Interesting that MB went backwards than we expected by adding things and not removing things such as oil pressure sensor not present on other MB engines and of course that good ol dipstick.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Apparently, the M256 has a combined oil pressure and temperature sensor (B149/1). I found the procedures for testing the oil pressure using XENTRY. In XENTRY, however, engine oil pressures can approach 4 bar. I will attach the initial procedures next.
What is interesting is that the images overlay both high/low pressure channels.
It might just be enough to tap a physical gauge into that spot and see what solenoid does near the filter (Before/After). Hopefully the car does not go into a strange limp situation with no pressure detected at the sensor. Did it show only XENTRY as the method for testing?
Note the blue arrows get larger and shows what looks like a blue piston cooling mist above the red arrows? I have a feeling that pressure sensor is just for the high pressure channel.
Apparently, the M256 has a combined oil pressure and temperature sensor (B149/1). I found the procedures for testing the oil pressure using XENTRY. In XENTRY, however, engine oil pressures can approach 4 bar. I will attach the initial procedures next.
Great discovery, this enables us to discover more about the changes MB made to the modern MB engines.
Great discovery, this enables us to discover more about the changes MB made to the modern MB engines.
Yep, that Benz Ninja C4 and software do cost $$
Thus investment is needed to learn more and real time/effort from Jetta.
Awesome Jet, many thanks....albeit I will never ever in my life buy any 48V dumb-azz mild hybrid based engine.
If I ever go electric, I will go full electric....maybe 20 more years, but me too old by then
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by S-Prihadi
Yep, that Benz Ninja C4 and software do cost $$
Thus investment is needed to learn more and real time/effort from Jetta.
Awesome Jet, many thanks....albeit I will never ever in my life buy any 48V dumb-azz mild hybrid based engine.
If I ever go electric, I will go full electric....maybe 20 more years, but me too old by then
It's really not that expensive for the value you get from it. About half the cost is in the equipment and software, and the other half is the technical expertise and services you get from Peter BenzNinja. Certainly far less than it would cost going to the dealer. How much are diagnostic fees at the dealer now? When my daughter had a problem with the steering lockup on her 2010 Lexus, the Lexus dealer estimated about $600 for diagnosing a known problem. The one-time life-time membership fee to the BenzNinja Club is a bargain! Plus, you get the membership fee credited to be used on future modifications!
Yeah, I'm gonna wait on the whole EV thing. It's not the concept I worry about; it's the implementation.
It's really not that expensive for the value you get from it. About half the cost is in the equipment and software, and the other half is the technical expertise and services you get from Peter BenzNinja. Certainly far less than it would cost going to the dealer. How much are diagnostic fees at the dealer now? When my daughter had a problem with the steering lockup on her 2010 Lexus, the Lexus dealer estimated about $600 for diagnosing a known problem. The one-time life-time membership fee to the BenzNinja Club is a bargain! Plus, you get the membership fee credited to be used on future modifications!
Yeah, I'm gonna wait on the whole EV thing. It's not the concept I worry about; it's the implementation.
BenzNinja is just basically XENTRY for the common man?
Very interested in it since our family has all MB and i have been wanting to get rid of the start/stop in the s580 for a loooong time
What is interesting is that the images overlay both high/low pressure channels.
It might just be enough to tap a physical gauge into that spot and see what solenoid does near the filter (Before/After). Hopefully the car does not go into a strange limp situation with no pressure detected at the sensor. Did it show only XENTRY as the method for testing?
Note the blue arrows get larger and shows what looks like a blue piston cooling mist above the red arrows? I have a feeling that pressure sensor is just for the high pressure channel.
Good research!
This looks like a single pressure valve gating all piston sprayers at once.
Use better viscosity to open it at lower Rpm.
So this setup has no dual-rate pump, right?
Only a squirter control, right?
++++ outcome...
circulating heat out of pistons is going to preserve much needed engine cyl. balance.
Meaning good oiling is going to make your engine run great once pistons rings + ECU maps adapt to it.
Stock setup is going to be laggy weak engine behaving old prematurely.
++++ SOLENOID valve is mechanical only!
the oil control is a basic pintle and spring.
It simply is pressure based without any electrical control by ECU.
It maintains general engine oiling at the expense of dry pistons with stuck leaky rings... amazin'
This ensures no starvation below ~30Psi. When pump volume is too low to supply piston sprayers, the valve shuts off supply.
> WIN-WIN:
To work this valve open, experiment with supplying enough pressure at driving Rpm to keep pistons rings clean without burnt carbon.
Last edited by CaliBenzDriver; Mar 3, 2025 at 04:40 PM.
OPS was disconnected last year on my M278 due to detailed contributions in this thread. Thank you.
when I pull her out of indoor storage, and I turn the key to all power on BUT I have not started the engine yet,
is the oil pump working, circulating (cold) oil, and attempting to lubricate the engine?
Or does the oil pump (with disconnected solenoid) only engage with a running engine?
I am trying to determine whether I can lubricate the engine internals before starting the engine, especially after it has been sitting for a long period of time. TIA
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
may be not in Holland, thus there is a term called Let's go On Dutch on our 1st date
The one-time life-time membership fee to the BenzNinja Club is a bargain! Plus, you get the membership fee credited to be used on future modifications!
